First Online: 21 August 2014Received: 21 May 2014Accepted: 07 August 2014

Abstract

BackgroundAbnormal ventricular repolarization is a predictor of cardiovascular mortality. In this study, we tested the hypothesis that glycemic control reverses abnormal ventricular repolarization in patients with type 2 diabetes.

ResultsIn the diabetic group, BMI was greater, levels of HbA1c 10.0 ± 1.6 vs. 5.6 ± 0.3% and triglyceride were higher and level of HDL cholesterol was lower than those in the control group. Although mean QTc intervals were similar 413.6 ± 18.5 vs. 408.3 ± 22.7 ms, QT dispersion 41.8 ± 15.4 vs. 28.7 ± 7.7 ms and Tpeak-Tend in lead V5 83.6 ± 13.6 vs. 71.3 ± 10.3 ms were significantly longer in the diabetic group than in the control group, indicating increased heterogeneity of ventricular repolarization in type 2 diabetes. During follow-up of 36 patients in the diabetic group for 787 ± 301 days, HbA1c level decreased to 7.3 ± 1.6%, while BMI did not significantly change. In contrast to HbA1c, QT dispersion 45.8 ± 15.0 ms and Tpeak-Tend in lead V5 83.6 ± 10.6 ms were not significantly reduced during the follow-up period. There was no correlation between the change in HbA1c and the change in QT dispersion or Tpeak-Tend.

ConclusionsIncreased heterogeneity of ventricular repolarization in type 2 diabetic patients was not reduced during the relatively short follow-up period despite significantly improved glycemic control.